Mining accidents are still a regular occurrence, often resulting in the loss of dozens of lives. Many of these fatalities could have been averted had there been a reliable emergency communications system in place to provide life-saving information to search-and-rescue parties and to trapped miners. To address this problem, Physical Optics Corporation (POC) proposes to develop a handheld transceiver for two-way through-the-earth communications (voice, text, and beacon), based on novel transceiver hardware and data processing algorithms, designed for operation in the 1 Hz to 10 kHz band. Operation in the extremely low frequency (ELF) and very low frequency (VLF) bands ensures that mine-to-surface communications can be maintained in all emergency situations. Innovations in the receiver enable maintaining a communication link with a surface transmitter through more than 2000 ft of overburden with only a handheld device no larger than a walkie-talkie. Underground transmitter power is limited, both for safety and for battery longevity-a zero-power beacon is included for situations where battery power is completely depleted. Application of customized digital noise reduction data processing allows the surface receiver to detect the weak signals arriving from the underground transmitter, amid the mine environmental noise. These advantages also make the proposed transceiver commercially attractive, since it is based largely on integration of existing technology, and potential markets include not only mine safety, but also the construction and energy industries, in addition to numerous military and security applications. As a result, POC's proposed research will significantly and positively impact the safety of personnel involved in underground operations by providing a reliable, compact, through-the-earth communications system. This directly supports the mission of the National Institute for Occupational Safety and Health to improve safety and health of mining workers. The goal of Phase I is to determine the longest range and highest data rate that can reliably be achieved for communication between a surface rescue team and an underground miner with only a handheld-sized device, based purely on through-the-earth communication that is completely safe for mine use, without relying on additional infrastructure. POC plans to demonstrate the feasibility of the concept by designing and assembling a breadboard prototype to confirm the transmit/receive characteristics of the design. The Phase I project will establish a solid scientific foundation and define the major performance and technical parameters for the full-scale engineering of a mature fully functional prototype that will be tested for operation in a mine environment in Phase II. POC will ensure the design meets Mine Safety and Health Administration regulations. Successful development of this technology will result in an entirely new emergency communications system that will overcome the safety, reliability, power, and size issues of current mine communications technology. PUBLIC HEALTH RELEVANCE: The proposed handheld radio transceiver will offer two-way voice, text, and data communications for underground mine workers that can be used to communicate with search and rescue teams on the surface in case of a mine emergency such as fire, explosion, or roof cave-in. Fully compliant with mine safety regulations, the transceiver offers robust communication through up to 2000 ft overburden.